A Path to the Future - Continuous Composite 3D Printing

It's not the introduction of great new technologies which ultimately proves transformative, it's the work done in small shops behind the scenes on the very real problems of making technologies useful that proves to be the keystone to the future.

Tyler and his team have been researching new extrusion methods intended to create lightweight and strong parts using "continuously composite paths." It's aimed at cutting resin use up to 70 percent while providing high-strength parts by precisely placing continuously composite paths using additive processes.

Working with Barbara and Martin Mueller, the expert machinists and lens-makers famous for inventing and developing the Imax Camera, has proven invaluable to Tyler in completing the precision machine work on the CC3D extruder head and optics. Along with the work at a makerspace in Coeur d'Alene called Gizmo, Tyler is collaborating with Mueller and Chris Beaty's company called ExtraTech, a robotics company specializing in motor-control hardware.

The core of the idea is how the device can utilize a growing set of novel materials which mark a departure from current methods of employing such materials.

The primary component in the process is a liquid curable material and the secondary component a solid, continuous strand of fiber. The secondary material is fed through a nozzle with the primary material and is entirely surrounded by the primary material during the extrusion phase. Once the composite material is extruded, it's cured to become what Tyler calls a "solid composite path."

"Utilizing the strength of the continuous fiber to our advantage during the print yields more flexibility and scalability. By combining print heads together it will be possible to print objects such as an I-beam or Hollow Tube into free space or at zero gravity with ease," Tyler says. "These hollow structures may be filled with foam or left hollow for utility. Much of what is created in nature is fibrous and hollow, yet provides great strength. The building you live in is most likely composed of hollow framed walls with materials attached to wood which is, in its nature around 70 percent dry, fibrous material. It makes sense to 3D print with the grain of nature, and the continuous fiber method is essentially a biomimetic approach to additive manufacturing."

Working with Ken Kratsch, a composites expert responsible for the development of multidimensional, composite materials, Tyler says the goal is to be able to print with single filaments of fiber just a few microns across.

The best primary materials, at least at this point in development, are epoxy resins, polyester resins, cationic epoxies, acrylated epoxies, urethanes, esters, thermoplastics, photopolymers, polyepoxides or even metals and metal alloys.

The CC3D device uses an energy curing processing unit to control a set of ultraviolet lights aimed at the path just after the point of extrusion. As the light turns on and off at the beginning and ending of paths, the processing unit may also administer an intermediate light intensity.

According to Tyler, his printer includes several ultraviolet lights around the point of extrusion which are capable of curing the path from multiple angles.

He says this is the first 3D printer to extrude a continuous fiber and resin combination by letting the movement of the machine pull it through the system. In this case, the UV light is creating a photoionic reaction that instantly hardens the path of material as soon as it appears from the end effector, or syringe-tip.

"This unique method allows us to use tension forces to our advantage and print into any direction, including free space," Tyler says. "One application we're looking at, for instance, is the possibility of mixing an epoxy thermoset binder, a ceramic filler and continuous Kevlar fiber to create a ballistics printable material for custom form fitting body armor."